Passive vibration isolating system

ABSTRACT

A passive vibration isolating system includes a sliding piece having its lower portion mounted on a base member and a first contact surface defined between the lower portion of the sliding piece and the top portion of the base member, and a supporting member mounted on the upper portion of the sliding piece and a second contact surface defined between the bottom portion of the supporting member and the upper portion of the sliding piece. At least one of the first and second contact surfaces is a curved surface with a concave-convex engagement.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present invention is a divisional application of the co-pending U.S. Ser. No. 08/880,583, filed on Jun. 23, 1997, now U.S. Pat. No. 6,021,992.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a passive vibration isolating system.

2. Description of the Related Art

The closest prior art of which the applicant is aware is disclosed in U.S. Pat. No. 4,320,549 to Greb, filed on Jul. 5, 1979, entitled "ROCKER-SLIDING BEARING ASSEMBLY AND A METHOD OF LINING THE ASSEMBLY".

A first conventional passive vibration isolating system in accordance with the prior art shown in FIGS. 7-9 comprises a plurality of lead rubber bearings 80 each of which is mounted between a building 62 and a ground base 60. Each of the lead rubber bearings 80 includes a base plate 81 fixedly mounted on the ground base 60, a supporting plate 82 fixedly mounted on an underside of the building 62, a rubber pad 83 supported between the base plate 81 and the supporting plate 82, and a lead column 84 mounted in a center of the rubber pad 83 and located between the base plate 81 and the supporting plate 82.

In operation, when an earthquake occurs, the base plate 81 is moved with the ground base 60 along the direction indicated by an arrow as shown in FIG. 9 to exert a shearing force on the lead rubber bearing 80, thereby deforming the rubber pad 83 and the lead column 84. In the meantime, the supporting plate 82 together with the building 62 is only slightly displaced by means of a plastic deformation or yielding effect of the lead column 84, thereby decreasing the displacement of the building 62 due to the sliding motion of the ground base 60, and thereby efficiently isolating the building 62 from the vibration created by the earthquake.

Referring to FIG. 8, the displacement A of the building 62 fitted with the lead rubber bearing 80 is much smaller than the displacement B of the building 62 without the lead rubber bearing 80. However, the rubber pad 83 will be worn out after long-term utilization, thereby decreasing the vibration isolating effect. In addition, the building 62 cannot be returned to its original position due to the plastic deformation of the lead column 84, thereby causing a deviation in the position of the building 62.

A second conventional passive vibration isolating system in accordance with the prior art shown in FIG. 10 comprises a plurality of pot bearings 90 each of which is mounted between a building (not shown) and a ground base (not shown). Each of the pot bearings 90 includes a base plate 91 fixedly mounted on the ground base and defining a recess 912 therein, a synthetic rubber 94 received in the recess 912, a bearing disk 93 fixedly mounted on the synthetic rubber 94, an elongated guiding rail 95 fixedly mounted on the bearing disk 93, a supporting plate 92 fixedly mounted on the underside of the building and defining a guiding groove 922 to slidably receive the guiding rail 95 therein, and a wear-resistant resin 96 coated between the bearing disk 93 and the supporting plate 92.

In operation, the supporting plate 92 together with the building can slide on the wear-resistant resin 96 along the guiding rail 95 when an earthquake occurs, thereby greatly decreasing the vibration caused by the earthquake. However, it is necessary to provide a damping mechanism for returning the building to its original position. In addition, the supporting plate 92 can only move along one direction, thereby greatly limiting the versatility of the pot bearing 90.

The present invention has arisen to mitigate and/or obviate the disadvantage of the conventional passive vibration isolating systems.

BRIEF SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention, there is provided a passive vibration isolating system which comprises a base member, a sliding piece having a lower portion mounted on the base member and a first contact surface defined between the lower portion of the sliding piece and a top portion of the base member, and a supporting member mounted on an upper portion of the sliding piece and a second contact surface defined between a bottom portion of the supporting member and the upper portion of the sliding piece. In such a manner, at least one of the first and second contact surfaces is a curved surface with a concave-convex engagement.

Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a partially cross-sectional perspective view of a passive vibration isolating system according to a first embodiment of the present invention;

FIG. 2 is a front plan cross-sectional view of the passive vibration isolating system as shown in FIG. 1;

FIG. 3 is an operational view of the passive vibration isolating system as shown in FIG. 2;

FIG. 4 is a partially cross-sectional perspective view of a passive vibration isolating system according to a second embodiment of the present invention;

FIG. 5 is a partially cross-sectional perspective view of a passive vibration isolating system according to a third embodiment of the present invention;

FIG. 6 is a partially cross-sectional perspective view of a passive vibration isolating system according to a fourth embodiment of the present invention;

FIG. 7 is a partially cross-sectional perspective view of a first conventional passive vibration isolating system in accordance with the prior art;

FIG. 8 is a front plan schematic view showing the first conventional passive vibration isolating system being fitted between a building and a ground base;

FIG. 9 is a partially enlarged view of the first conventional passive vibration isolating system as shown in FIG. 8; and

FIG. 10 is a partially cross-sectional perspective view of a second conventional passive vibration isolating system in accordance with the prior art.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIGS. 1-3, a passive vibration isolating system according to a first embodiment of the present invention comprises a positive and negative curve bearing 10 which includes a base member 12 fixedly mounted on a ground base 50, a sliding piece 16 having its lower portion mounted on the base member 12 and a first contact surface defined between the lower portion of the sliding piece 16 and the top portion of the base member 12, and a supporting member 14 fixedly mounted on the underside of a building 52 and supported on the upper portion of the sliding piece 16, and a second contact surface defined between the bottom portion of the supporting member 14 and the upper portion of the sliding piece 16. Each of the base member 12, the supporting member 14 and the sliding piece 16 is made of a rigid metal. By such an arrangement, at least one of the first and second contact surfaces is a curved surface with a concave-convex engagement.

In practice, the base member 12 includes a lug 120 protruding upward from the top portion thereof and defining a recess 121 therein. A bearing piece 122 is securely received in the recess 121 and has its top portion forming a first concave curved surface 123. A natural rubber 125 is snugly received in the recess 121 and supported on the bottom portion of the bearing piece 122. The supporting member 14 includes a lip 140 protruding downward from the bottom portion thereof and forming a second concave curved surface 141.

It is to be noted that the first concave curved surface 123 opens upward and has a positive curve, and the second concave curved surface 141 opens downward and has a negative curve such that the bearing 10 is called a positive and negative curve bearing.

The sliding piece 16 includes a first convex curved surface 163 formed on the lower portion thereof, and a second convex curved surface 162 formed on the upper portion thereof. A first wear-resistant resin layer 124 is coated on the first concave curved surface 123 and slidably abutting the first convex curved surface 163, and a second wear-resistant resin layer 142 is coated on the second concave curved surface 141, and slidably abutting the second convex curved surface 162.

In operation, referring to FIGS. 2 and 3 with reference to FIG. 1, a plurality of positive and negative curve bearings 10 are each mounted between the building 52 and the ground base 50. When the ground base 50 is displaced sideways due to an earthquake, the base member 12 together with the bearing piece 122 of each of the positive and negative curve bearings 10 is moved with the ground base 50 while the sliding piece 16 is slidably displaced between the bearing piece 122 and the supporting member 14 such that the supporting member 14 together with the building 52 is only slightly displaced, thereby decreasing a sliding deviation of the building 52 due to the sliding motion of the ground base 50, and thereby efficiently isolating the building 52 from a horizontal vibration (or shock) created by the earthquake. The first and second wear-resistant resin layers 124 and 142 are used to damp the sliding motion between the sliding piece 16, the supporting member 14 and the bearing piece 122.

When the earthquake stops, the building 52 together with the supporting member 14 is returned to its original position, as shown in phantom lines in FIG. 3, due to the sliding engagement between the sliding piece 16, the supporting member 14 and the bearing piece 122. By such an arrangement, the building 52 relies on its weight to return to its original status without using an additional spring returning device or damping mechanism. In addition, the bearing piece 122 can sway on the natural rubber 125 due to the elastomeric feature of the natural rubber 125 such that the building 52 can be rotated around a slight angle along a horizontal axis thereof, thereby absorbing a vertical vibration created by the earthquake.

Referring now to FIG. 4, a passive vibration isolating system in accordance with a second embodiment of the present invention comprises a negative curve bearing 10A which includes a base member 12 having a top portion forming a lug 120 protruding upward and defining a recess 121 therein. A supporting member 14 has a bottom portion forming a lip 140 protruding downward and forming a concave curved surface 141. A sliding piece 16A includes a lower portion securely received in the recess 121, and an upper portion forming a convex curved surface 162A. A wear-resistant resin layer 142 is coated on the concave curved surface 141, and slidably abutting the convex curved surface 162A. A natural rubber 125 is snugly received in the recess 121 and is supported on the lower portion of the sliding piece 16A. The operation of the negative curve bearing 10A is similar to that of the positive and negative curve bearing 10 and will not be further described. It is to be noted that the concave curved surface 141 opens downward and has a negative curve such that the bearing 10A is called a negative curve bearing.

Referring now to FIG. 5, a passive vibration isolating system in accordance with a third embodiment of the present invention comprises a positive curve bearing 10B which includes a base member 12 having a top portion forming a lug 120 protruding upward and forming a concave curved surface 123. A sliding piece 16B has a lower portion forming a convex curved surface 163B and an upper portion defining a recess 166 therein. A wear-resistant resin layer 124 is coated on the concave curved surface 123 and slidably abutting the convex curved surface 163B. A supporting member 14 has a bottom portion forming a lip 140 protruding downward and securely received in the recess 166. A natural rubber 168 is snugly received in the recess 166 and is supported on the bottom portion of the lip 140. The operation of the positive curve bearing 10B is similar to that of the positive and negative curve bearing 10 and will not be further described. It is to be noted that the concave curved surface 123 opens upward and has a positive curve such that the bearing 10B is called a positive curve bearing.

Referring now to FIG. 6, a passive vibration isolating system in accordance with a fourth embodiment of the present invention comprises a positive curve bearing 10C which includes a base member 12 having a top portion forming a lug 120 protruding upwardly and defining a recess 121 therein. A bearing piece 122 is securely received in the recess 121 and has a top portion forming a concave curved surface 123. A natural rubber 125 is securely received in the recess 121 and is supported on a bottom portion of the bearing piece 122. A supporting member 14 has a bottom portion forming a lip 140 protruding downward and forming a convex curved surface 143. A wear-resistant resin layer 124 is coated on the concave curved surface 123 and slidably abutting the convex curved surface 143. The operation of the positive curve bearing 10C is similar to that of the positive and negative curve bearing 10 and will not be further described.

It should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention. 

What is claimed is:
 1. A passive vibration isolation system comprising:a base member including a lug protruding upwardly from a top portion thereof and defining a recess therein; a natural rubber snugly received in said recess and supported within the recess of said base member; a bearing piece mounted on said natural rubber and securely received within said recess of said base member and including a convex curved surface formed on an upper portion thereof; and a supporting member mounted on an upper portion of said bearing piece and including a bottom portion forming a concave curved surface slidably abutting said convex curved surface.
 2. The passive vibration isolating system according to claim 1, further comprising a wear-resistant resin layer coated on said concave curved surface, and abutting said convex curved surface.
 3. A passive vibration isolation system comprising:a base member including a lug protruding upwardly from a top portion thereof and defining a recess therein; a natural rubber snugly received in said recess and supported within the recess of said base member; a bearing piece mounted on said natural rubber and securely received within the recess of said base member and including a concave curved surface formed on an upper portion thereof; and a supporting member mounted on an upper portion of said bearing piece and including a bottom portion forming a convex curved surface slidably abutting said concave curved surface.
 4. The passive vibration isolating system according to claim 3, further comprising a wear-resistant resin layer coated on said concave curved surface, and abutting said convex curved surface.
 5. A passive vibration isolation system comprising:a base member including a top portion defining a concave curved surface therein; a bearing piece mounted on said base member and including a bottom portion defining a convex curved surface slidably abutting said concave curved surface and a lug protruding upwardly from a top portion thereof and defining a recess therein; a natural rubber snugly received in said recess and supported within said recess of said bearing piece; a supporting member including a bottom portion mounted on said natural rubber and securely received within the recess of said bearing piece.
 6. The passive vibration isolating system according to claim 5, further comprising a wear-resistant resin layer coated on said concave curved surface, and abutting said convex curved surface. 